1. Field of the Invention
The present invention relates to a semiconductor device such as a transistor module in which an internal connecting terminal held by an insulating member forming an upper container cover is brazed onto circuit wiring connected to a semiconductor element on a circuit board when the semiconductor element secured onto the circuit board are connected to the internal connecting terminal.
2. Discussion of the Related Art
FIGS. 7, 8 show a conventional construction of a prior art semiconductor device. As shown in FIGS. 7, 8, the prior art semiconductor device comprises a circuit board 1, semiconductor elements 3, a leading-out terminal 15a which, before being led out, is soldered onto a circuit wiring pattern 2 stuck to the circuit board 1, a metal radiating plate 11, a container 5 combining the metal radiating plate 11, an upper cover 5a and side walls 5b made of resin, a gelatinous silicone resin layer 16, and an epoxy resin layer 17.
A soldering leg 15c bent in an L shape and a curved damper 15b for setting thermal stress free are formed at the trailing end and the intermediate portion of the leading-out terminal 15a, respectively. The upper end of that terminal 15a is passed through and led out of the upper cover 5a.
The conventional semiconductor device is assembled in the following way. First, the semiconductor element 3 is joined onto the circuit board 1 by die bonding, the radiating plate 11 being fastened to the undersurface of the circuit board under a different process beforehand. Then the leading-out terminal 15a, passed through and secured to the upper cover 5a of the container 5, is mounted on the circuit board 1. In this state, the leg 15c of the terminal 15a is subsequently joined onto the circuit wiring 2 by reflow soldering. Although there is shown only one terminal 15a in FIG. 7, a plurality of leading-out terminals are secured to the upper cover 5a of the container 5 in an actual semiconductor device. These leading-out terminals are uprightly projected from the board 1. After the reflow soldering is completed, side walls 5b of the container 5 are secured to the metal radiating plate 11 and then an empty space inside the container 5 is filled with silicone resin 16 through the gap between the upper cover 5a and the side wall 5b. Further, epoxy resin 17 is injected into the remaining space on the upper layer side and hardened in order to resin-seal the container 5.
The conventional semiconductor device described above, particularly the leading-out terminal construction, has posed the following problems in view of assembly precision, parts handling and the like. As the leading-out terminal 15a is made by pressing a metal sheet, it may be deformed by external force when it is stored or handled. On the other hand, if the terminal becomes deformed even slightly, it will be difficult to secure the flatness and positional accuracy of the terminal leg 15c by soldering during assembly as described above. This forms the determining cause for defective soldering with respect to the circuit board 1. In the case of a semiconductor device in which the position of the terminal 15a set and soldered onto the circuit wiring 2 of the circuit board 1, and that of leading out the external terminal disposed on the upper cover 5a of the container 5, are separated as viewed from a horizontal plane, various individually designed and different by dimensioned and shaped leading-out terminals will be required in line with the circuit wiring 2.
With the conventional terminal construction left intact, it is difficult to not only standardize the configurations and dimensions of terminal parts for use in semiconductor devices having more than one kind of circuit wiring 2, different in wiring pattern, but also obtain a high degree of dimensional tolerance at the time of assembly and this causes an increase in cost.